Method for measuring arsenic content in cobalt

Abstract

The invention discloses a method for measuring arsenic content in cobalt. The method comprises the following steps: pretreating a cobalt compound sample; the pretreated cobalt compound sample is introduced into an inductively coupled plasma mass spectrometer, detection is carried out in a collision mode with inert gas as carrier gas, the inert gas is helium, and the flow of the helium is 4.5-5.5 ml / min. According to the detection method, interference of cobalt on arsenic content detection can be effectively reduced, the accuracy of detection of the arsenic content in the cobalt compound can be improved, and the performance of a cobalt precursor product can be determined.

Description

Technical Field

[0001] This application relates to the technical field of arsenic content detection, and particularly to a method for determining the arsenic content in cobalt. Background Art

[0002] Cobalt compounds are cobalt-containing CVD / ALD precursors used to manufacture important functional layers of devices. It is an important precursor for preparing cobalt metal, cobalt nitride, cobalt silicide, etc. The level of arsenic in cobalt compounds directly affects the performance of products. Therefore, it is very necessary to accurately determine the arsenic content in cobalt.

[0003] Common methods for detecting arsenic content include atomic absorption spectrometry (AAS). This method is simple, fast, and highly proficient, and has been applied to the detection of arsenic content in various industries. However, when using atomic absorption spectrometry to determine the arsenic content in cobalt, the cobalt matrix seriously interferes with the detection of arsenic content, resulting in a low detection range and an inability to accurately measure the arsenic content in cobalt.

[0004] The information disclosed in this background art section is only intended to enhance the overall understanding of this application and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of this application is to provide a method for determining the arsenic content in cobalt, so as to solve the technical problem that when the existing technology is used to determine the arsenic content in cobalt, the cobalt matrix seriously interferes with the detection of arsenic content, resulting in a low detection range and an inability to accurately measure the arsenic content in cobalt.

[0006] To achieve the above purpose, a technical solution adopted by this application is:

[0007] Provide a method for determining the arsenic content in cobalt, including:

[0008] Pretreat the cobalt compound sample;

[0009] Inject the pretreated cobalt compound sample into an inductively coupled plasma mass spectrometer and detect it with an inert gas as the carrier gas in the collision mode.

[0010] In one or more embodiments, the inert gas is helium.

[0011] In one or more embodiments, the flow rate of the helium is 4.5 - 5.5 ml / min.

[0012] In one or more embodiments, the flow rate of the helium is 5 ml / min.

[0013] In one or more embodiments, the step of pretreating the cobalt compound sample includes: adding the cobalt compound sample to nitric acid for dissolution, and then diluting with water.

[0014] In one or more embodiments, in the step of adding the cobalt compound sample to nitric acid for dissolution and then diluting with water, the concentration of the nitric acid is 5%, and the concentration of the cobalt compound after dilution with water is 1 ppb.

[0015] In one or more embodiments, in the step of injecting the pretreated cobalt compound sample into an inductively coupled plasma mass spectrometer and detecting it with an inert gas as the carrier gas in the collision mode, the radio frequency power of the inductively coupled plasma mass spectrometer is 1600 w.

[0016] In one or more embodiments, the cobalt compound is bis(3,3-dimethyl-1-butynyl)cobalt hexacarbonyl.

[0017] In one or more embodiments, the detection range of arsenic content in the determination method is 0.2 - 20 ppm.

[0018] Different from the prior art, the beneficial effects of this application are:

[0019] The detection method of this application can effectively reduce the interference of cobalt on the detection of arsenic content, contribute to improving the accuracy of arsenic content detection in cobalt compounds, and help to clarify the performance of cobalt precursor products. Description of the Drawings

[0020] Figure 1 is a schematic flow chart of an embodiment of the method for determining arsenic content in cobalt of this application. Detailed Embodiments

[0021] The following will describe the detailed embodiments of this application with reference to the drawings, but it should be understood that the protection scope of this application is not limited by the detailed embodiments.

[0022] Unless otherwise clearly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "having" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0023] Currently, the detection method of arsenic content mainly uses atomic absorption spectrometry (AAS). This method is simple, fast, and highly proficient, and has been applied to the detection of arsenic content in various industries. However, when using atomic absorption spectrometry to determine the arsenic content in cobalt, the cobalt matrix seriously interferes with the detection of arsenic content, resulting in a low detection range and being unable to accurately measure the arsenic content in cobalt.

[0024] Inductively coupled plasma mass spectrometry (ICP-MS) has the advantages of high sensitivity, low sample consumption, fast speed, low detection limit, and wide linear range, and is mainly applied in the detection of high-purity precursor products. Applying inductively coupled plasma mass spectrometry to the detection of arsenic content in cobalt precursors will be more advantageous. However, how to exclude the interference of cobalt on arsenic detection in inductively coupled plasma mass spectrometry to ensure the accuracy of arsenic content detection is a problem that needs to be studied.

[0025] To solve the above problems, the applicant has developed a method for determining the arsenic content in cobalt, which can effectively avoid the interference of cobalt matrix on arsenic detection, thereby improving the accuracy of arsenic content detection.

[0026] Specifically, please refer to Figure 1 , Figure 1 which is a schematic flow diagram of an embodiment of the method for determining the arsenic content in cobalt of this application.

[0027] The determination method includes:

[0028] S100. Pretreat the cobalt compound sample.

[0029] First, pretreat the cobalt compound sample. The pretreatment method can be to dissolve the cobalt compound in nitric acid and then dilute it to achieve complete digestion of the cobalt compound and impurities.

[0030] In one embodiment, nitric acid with a concentration of 5% can be used to dissolve the cobalt compound.

[0031] In one embodiment, after dilution with water, the concentration of the cobalt compound can be 1 ppb.

[0032] In one embodiment, the cobalt compound sample can be a (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl sample. In other embodiments, it can also be other cobalt compound samples.

[0033] S200. Inject the pretreated cobalt compound sample into an inductively coupled plasma mass spectrometer and detect it with an inert gas as the carrier gas in the collision mode.

[0034] After pretreatment, inject the cobalt compound sample into an inductively coupled plasma mass spectrometer, select the collision mode at the same time, and detect it with an inert gas as the carrier gas.

[0035] In the collision mode, cobalt ions and arsenic ions collide with inert gas particles polarely. Since the number of cobalt ions is much larger than that of arsenic ions, cobalt ions will lose more kinetic energy during the forward process. When reaching the outlet of the collision reaction cell, the ion kinetic energy of cobalt ions decreases more significantly, which can effectively reduce the interference of cobalt on arsenic content detection.

[0036] In one embodiment, the inert gas can be helium.

[0037] In one embodiment, in order to achieve the optimal anti-interference effect for arsenic detection, the flow rate of helium can be 4.5 - 5.5 ml / min.

[0038] Preferably, in one embodiment, in order to optimize the response of the inductively coupled plasma mass spectrometer, the flow rate of helium can be 5 ml / min.

[0039] Based on the detection method of the above embodiment, it can effectively reduce the influence of cobalt on the detection of arsenic content, and contribute to improving the accuracy of measuring arsenic content in cobalt compounds.

[0040] The beneficial effects of the technical solution of the present application will be further introduced in detail below with specific embodiments.

[0041] Example 1:

[0042] Prepare a sample of bis(3,3-dimethyl-1-butynyl)cobalt hexacarbonyl with an arsenic content of about 0.2 ppm;

[0043] After pretreating the cobalt compound sample, inject it into an inductively coupled plasma mass spectrometer, and perform detection with helium as the carrier gas in the collision mode. The radio frequency power of the inductively coupled plasma mass spectrometer is 1600 w and the helium flow rate is 5 ml / min.

[0044] Example 2:

[0045] Inject the same sample as in Example 1 into an inductively coupled plasma mass spectrometer, and perform detection with helium as the carrier gas in the collision mode. The radio frequency power is 1600 w and the helium flow rate is 4.5 ml / min.

[0046] Example 3:

[0047] Inject the same sample as in Example 1 into an inductively coupled plasma mass spectrometer, and perform detection with helium as the carrier gas in the collision mode. The radio frequency power is 1600 w and the helium flow rate is 5.5 ml / min.

[0048] Comparative Example 1:

[0049] Inject the same sample as in Example 1 into an inductively coupled plasma mass spectrometer, and perform detection with helium as the carrier gas in the collision mode. The radio frequency power is 1600 w and the helium flow rate is 3 ml / min.

[0050] Comparative Example 2:

[0051] The same sample as in Example 1 was injected into an inductively coupled plasma mass spectrometer and detected in collision mode with helium as the carrier gas, with a radio frequency power of 1600 w and a helium flow rate of 4 ml / min.

[0052] Comparative Example 3:

[0053] The same sample as in Example 1 was injected into an inductively coupled plasma mass spectrometer and detected in reaction mode with ammonia as the carrier gas, with a radio frequency power of 1600 w and an ammonia flow rate of 0.6 ml / min.

[0054] Comparative Example 4:

[0055] The same sample as in Example 1 was injected into an inductively coupled plasma mass spectrometer and detected in reaction mode with ammonia as the carrier gas, with a radio frequency power of 1600 w and an ammonia flow rate of 0.8 ml / min.

[0056] Comparative Example 5:

[0057] The same sample as in Example 1 was injected into an inductively coupled plasma mass spectrometer and detected in reaction mode with ammonia as the carrier gas, with a radio frequency power of 1600 w and an ammonia flow rate of 1.0 ml / min.

[0058] Comparative Example 6:

[0059] The same sample as in Example 1 was injected into an inductively coupled plasma mass spectrometer and detected in reaction mode with ammonia as the carrier gas, with a radio frequency power of 1600 w and an ammonia flow rate of 1.2 ml / min.

[0060] Effect Example:

[0061] The arsenic content detection results of Examples 1 to 3 and Comparative Examples 1 to 6 are compared as follows:

[0062]

[0063] As shown in the above table data, the detection results of Examples 1 to 3 are much more accurate than those of Comparative Examples 1 to 6. This is mainly because in the detection methods of Examples 1 to 3, detection was carried out in collision mode with helium at an appropriate flow rate as the carrier gas. Cobalt ions and arsenic ions collided polar with helium particles. Since the number of cobalt ions is much larger than that of arsenic ions, cobalt ions will lose more kinetic energy during the forward process. When reaching the outlet of the collision reaction cell, the ion kinetic energy of cobalt ions decreases more significantly, which can effectively reduce the interference of cobalt on the detection of arsenic content.

[0064] Among them, during the detection process of Example 1, the instrument response degree of the inductively coupled plasma mass spectrometer is the best, and it is used as the optimal example.

[0065] Referring to the test results of Examples 1 to 3 simultaneously, it can be seen that the detection limit of the detection method of the present application is as low as 0.2 ppm, which helps to accurately measure the arsenic content in cobalt.

[0066] In Comparative Examples 1 and 2, the detection was also carried out with helium as the carrier gas in the collision mode, but the helium flow rate was too low to effectively reduce the interference of cobalt on the detection of arsenic content.

[0067] In Comparative Examples 3 to 6, the detection was carried out with ammonia as the carrier gas in the reaction mode, and the interference of cobalt on the detection of arsenic content was relatively large, affecting the detection accuracy.

[0068] The foregoing description of the specific exemplary embodiments of the present application is for purposes of illustration and exemplification. These descriptions are not intended to limit the present application to the precise forms disclosed, and obviously, many changes and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present application and its practical applications, so that those skilled in the art can implement and utilize various different exemplary embodiments of the present application, as well as various different selections and changes. The scope of the present application is intended to be defined by the claims and their equivalents.

Claims

1. A method for determining the arsenic content in cobalt, characterized in that, Comprising: Pre-treating a cobalt compound sample; Injecting the pre-treated cobalt compound sample into an inductively coupled plasma mass spectrometer and detecting it with an inert gas as the carrier gas in a collision mode.

2. The measurement method according to claim 1, characterized in that, The inert gas is helium.

3. The measurement method according to claim 2, characterized in that, The flow rate of the helium is 4.5 - 5.5 ml / min.

4. The measurement method according to claim 3, wherein The flow rate of the helium is 5 ml / min.

5. The measurement method according to claim 1, characterized in that, The step of pre-treating the cobalt compound sample includes: adding the cobalt compound sample to nitric acid for dissolution and then diluting with water.

6. The measurement method according to claim 5, characterized in that, In the step of adding the cobalt compound sample to nitric acid for dissolution and then diluting with water, the concentration of the nitric acid is 5%, and the concentration of the cobalt compound after dilution with water is 1 ppb.

7. The measurement method according to claim 1, wherein In the step of injecting the pre-treated cobalt compound sample into an inductively coupled plasma mass spectrometer and detecting it with an inert gas as the carrier gas in a collision mode, the radio frequency power of the inductively coupled plasma mass spectrometer is 1600 w.

8. The measurement method according to claim 1, characterized in that The cobalt compound is bis(3,3-dimethyl-1-butynyl)cobalt hexacarbonyl.

9. The measurement method according to any one of claims 1 to 8, characterized in that, The detection range of the arsenic content of the determination method is 0.2 - 20 ppm.

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